Why we study the geological record for evidence of the solar oscillation about the galactic midplane |
| |
| Authors: | John J Matese Patrick G Whitman Kimmo A Innanen and Mauri J Valtonen |
| |
| Institution: | (1) Department of Physics, The University of Southwestern Louisiana, USA;(2) Department of Physics, York University, Ontario, Canada;(3) Tuorla Observatory, University of Turku, Finland |
| |
| Abstract: | The Solar System oscillates about the plane defined by the disk of matter in our Galaxy. This oscillatory motion gives rise to a substantial modulation in the tidally induced flux of Oort cloud comets. An observational determination of the quasi-periodicity of this motion carries with it significant information about the population, distributions, dynamics and origins of short-period and long-period comets. An additional incentive for emphasizing such a study is the information about dark disk matter that a period can yield. If dark disk matter is completely negligible, the amplitude of the solar motion will be sufficiently large that the peak-to-trough flux ratio will be  2.5 and the plane-crossing period will exceed 40 Myr. Dark disk matter comparable in mass to bright disk matter and distributed in any manner is inconsistent with K-dwarf distributions and can be rejected as a working hypothesis. But if a modest fraction of the disk matter is dark and distributed like the interstellar medium, as is consistent with limits deduced from K-giant and K-dwarf velocity distributions, the peak-to-trough flux ratio can increase to a factor of 4 even though the solar z amplitude is decreased. In that case the period can be as little as 30 Myr and the implied Oort population is smaller by a factor of 3. We should carefully reconsider the geological record as a potential discriminator of these options. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
